Assessment of Radiation at Tin Mining Sites, in Jos South Local Government Area of Plateau State, Nigeria

International Journal of Scientific & Engineering Research Volume 12, Issue 7, July-2021 347 ISSN 2229-5518

Assessment of Radiation at Tin Mining Sites, In Jos South Local Government Area of Plateau State, Nigeria. Agwor N.E, Dr. Binbol N.L

Abstract— Mining has been identified as one of the potential sources of exposure to Naturally Occurring Radioactive Materials (NORM), as well as higher activity concentrations of primordial radionuclides in the topsoil of mining sites and their environs. This research focused on the assessment of radiation at tin mining sites in Jos North Local Government Area, Plateau State, Nigeria. Eleven sample sites were considered and measured using the hand held Geiger counter for radiation and temperature. GPS was also used to measure location and map out sample sites. GIS analysis, Wilcoxon signed rank test and spearman rank correlation coefficient were used to analyzed data obtained from field. Results showed that, samples sites measured in March have a higher mean value of 0.3227μSvh-1 than those measured in July with a mean value of 0.2545μSvh-1. Diurnal analysis showed that there was no significant variation with the time of day radiation readings were taken using Wilcoxon Signed Ranks Test, although annual radiation projection reveals that all sample site measurement are higher than the ICRP 2007 recommendation with up to 5mSvy-1 for the highest measured radiation readings of 0.72 μSvh-1. The study also proves that there is a significant relationship between the amount of emitted radiation and temperature. This research recommends that, the public should be made aware and most especially miners, to the dangers associated to radiation exposure as a result of mining and other manmade sources.

Dose: a measured level of radiation. μSv: microsievert. mSv: millisievert. Gy: Gray, unit of ionizing radiation. CPEP: Contemporary Physics Education Project. PHE: Public Health England. Exposure pathways: the physical course through which humans are contact radiation.

——————————  —————————— 1 Introduction ccording to the Nigeria Extractive Industries routinely and in accidents are what are commonly referred Transparency Initiatives (NEITI) audit report on to as “low doses” [3]. There is no precise definition of “low” A the solid minerals industry 2007-2010, over N2.21 but it would include doses below, for example, 10 mSv per billion was paid as royalty by operating companies, N51.4 year. Radiation doses above 3 Gy (300 rad) can be fatal and billion as taxes by some companies/major players in the doses above 6 Gy (600 rad) are almost certain to be fatal, industry. This indicates the lucrative nature of mining solid with death occurring within several months (in shorter minerals in the country. Mining is associated with by times at higher doses). Radiation that causes genetic products which might be IJSER radioactive, and emits waves damage, which directly damages the reproductive organs, which might be harmful to the miners, users of these by and therefore affects any offspring that individual may products for construction of houses, or even the prolong have after the damage has occurred. Radiation damage is exposure to it. Ionizing radiation has many practical uses in done to genes and chromosomes, which can be passed on medicine, research, construction, but present a health to future generations [4]. Studies of survivors of the hazard if used improperly. Hiroshima and Nagasaki bombings and of the Chernobyl According to Canadian Nuclear safety survivors in Ukraine have shown that there are increased Commission[1] there are three main types of radioactive rates of stillbirths, miscarriages, and infant death [5]. decay, these are: Alpha decay, Beta decay and Gamma According to Ibrahima, Aliyub, Najibc and Hamza decay: This takes place when there is residual energy in the [6], radiation exposure associated with tin mining sites nucleus following alpha or beta decay, or after neutron around Toro area in Bauchi State were above the safety capture (a type of nuclear reaction) in a nuclear reactor. The limit recommended for the public by International sources of these radiations according to the United Nations Commission on Radiological Protection (ICRP). Similarly, Scientific Committee on the Effects of Atomic Radiation [2] Wapwera, Ayanbimpe and Odit [7] observed the traces of include exposure from cosmic radiation, exposure from X-ray, beta-ray and gamma-ray as well as the heavy metals terrestrial radiation, exposure through inhalation, exposure such as Lead, Arsenic , cadmium, chromium and nikel through ingestion: trace amounts of radioactive minerals which exceeded the international standards around are naturally found in the contents of food and drinking abandoned mine in Jos plateau. Aigbedion [8] conducted a water. For instance, vegetables are typically cultivated in research in Jos-Plateau State about the mysterious deaths of soil and ground water which contains radioactive minerals. tin miners who used most of the byproducts of tin mining Most of the radiation doses that are received by for construction and attributed their deaths to high level of members of the public and by radiation workers both radiation released by monazites-rich sand used for building

IJSER © 2021 http://www.ijser.org International Journal of Scientific & Engineering Research Volume 12, Issue 7, July-2021 348 ISSN 2229-5518 the houses the deceased lived in. This present research is therefore geared towards assessing the level of radiation emission at selected tin mining site in Jos South Local Government Area of Plateau State. In order to achieve this, the research will strive to:

 Measure and analyse the amount of emitted radiation in the various towns in Jos South local Government Area, Plateau State.  analyze seasonal radiation and temperature variations at the mined sites  Proffer possible ways in reducing radiological hazards.

2 Study Area Jos south local government area in Plateau State, Nigeria is located on coordinate 90 46N to 90.76N and 8048’E to 80.80E.It has a total land area of about 5,104km2 (1,971 sq mi) see figure 1 and 2. According to the 2006 population census Jos South has a population of 306,716 and a density of 604/km2. It is the second most populated local government area in the state after Jos North. The major mineral resources found in the study area are tin ore, cassiterite (Sn02), columbite and calcium carbonate (CaC03). The area extent of devastated arable land by open-cast tin Figure 1: Map of Nigeria Showing Plateau State and Study mining is estimated at 316km2, which comprises of mine Area (Jos South) spoils, pits, paddocks, and site of abandoned equipment, mining scar, tailing, mine dumps and ponds, especially along the river valleys [9]. Balogun [10] pointed out that the Jos Plateau mining region covers an area of approximately 3,670km2, about 43% of the totalIJSER land area of Jos Plateau.

Source: Plateau state Geographic Information Site, 2016.

Figure 2: Map of Jos South showing towns in study area. Source: Plateau state Geographic Information Site, 2016.

4 Literature Review 3 Material and Methods Mining the earth of minerals has result in diverse Data on the amount or level of radiation was environmental hazards, ecological disturbance and collected in situ using an instrument called the Geiger disturbance of flora and fauna, pollution of air, land and counter (RadEye G gamma survey meter), the instrument water, instability of soil and rock masses, landscape was also used to measure the temperature as at when degradation and radiation. In recent years little attention is radiation readings were taken. Samples each were given to radiation because its effect is not immediate. In a measured from Guratopp, Rayfield, Turu, Giring, Bukuru, research conducted by Wapwera, Ayanbimpe and Odit [7], Du and Zawan, to cover the Jos South Local Government deaths of tin miners within Jos, were attributed to the use of Area, these samples was collected around February/March mining by products for building, In the developed and then June/July and subjected to further statistical test to countries such as members of the European Union (11), show variability. each member country is obliged to identify work activities Field data collected from sampled site were that cannot be ignored from the radiological protection organized and input into excel with their coordinate, then point of view. This action has increased the awareness of ArcGis was used to extract the excel file and then the potential problems enormously, and most of the EU georeferenced before interpolating the data, in order to member states have now implemented regulations produce a map for both radiation and temperature base on dedicated to natural sources of exposure [11]. Recently the data obtain from the field. Frequency tables, charts and there are a lot of reports on natural occurring radioactive maps, were also used to present the analyzed data. The materials (NORM) with respect to occupational and public Wilcoxon signed-rank test was used to show variation exposure situations that have been published recently [12], using the median between dry season and wet season. [13], [14] that have all contributed significantly to the Since the sample size are equal and the two groups of recognition of the radiological consequences and risk observation are on the same population, the most associated with NORM. On the average, the annual global appropriate statistical tool to use was the Wilcoxon signed- effective dose due to exposure to NORM has been rank test, also the Wilcoxon signed-rank test was used to estimated to be 2.4 millisievert (mSv) with a typical range test the diurnal variability of radiation. The formula for the between 1-10 mSv [15]. Wilcoxon signed-rank test isIJSER given as However, specific individuals residing near 푅 − 휇푅 installations releasing radioactive materials into the 퓏 = 휎푅 environment may be subjected to higher exposures. It 푛1(푛1+푛2 + 1) should be noted that, should some of the sites with high 휇푅 = 2 levels of radioactive residues be inhabited or re-inhabited,

푛1푛2(푛1+푛2 + 1) the settlers would incur radiation exposures that would be 휎 = √ 푅 12 higher than the global average level of natural exposures Where [15]. This is a contrary case as Gbarato, Osimobi and Avwiri [16] measured the Background Gamma Radiation Level of R= sum of ranks for smaller sample size (푛1) n1= smaller of the sample size Udi, Enugu-South And Ezeagu Lgas Of Enugu State, the n2= larger of sample size results of the background ionizing radiation measurements To further analyse the data collected to show if from the measurement points around each of the solid there is relationship between emitted radiation and mineral sites studied shows that the exposure dose rate temperature the spearman rank correlation coefficient was ranged from 0.010 mR/hr to 0.025 mR/hr with an average of used to measure the 0.014 mR/hr at location 1 (Amagu-Umuene), 0.012 mR/hr to strength of the link between the paired x (emitted 0.022 mR/hr with an average of 0.0165mR/hr at the location radiation)and y (temperature) values of the sample data 2 (Ogulogo-olo) and 0.011 mR/hr to 0.022 mR/hr with an collected. Where d2 =difference between the two ranks of average of 0.0153 mR/hr at location 3 which are populated each observation, n = number of observations and R= region in the south east of Nigeria. Spearman’s arnk correlation coefficient The level of radiological hazards associated with the activities of tin mining and milling in most cases are detrimental to physiology of the human for instance, IJSER © 2021 http://www.ijser.org International Journal of Scientific & Engineering Research Volume 12, Issue 7, July-2021 350 ISSN 2229-5518 measurement of Radionuclides in processed tin mine tailings in Jos using NaI(TI) detector by Mangset and Figure 3: Map of March Radiation Measured Sheyin [17] shows that the mean activity concentration ranged from 364Bq/kg-27930Bq/kg in the tailings. Similarly HPGe detector used to measure the radioactivity in mine tailings in Jos, revealed that 226Ra (radium) have mean activity concentration ranged between 51.36Bq/kg – 512.24Bq/kg while 232Th (thorium) mean concentrations ranged between 378.02Bq/kg – 2635.78Bq/kg [18]. These measurements show high radionuclide readings within the Jos Plateau. These high readings were also observed by Usikalu M.R, Anoka O.C and Balogun F.A [18], who measured radioactivity of the Jos Tin Mine Tailing in Northern Nigeria, discovered that the activities of 226Ra and232Th are much higher than the recommended average limit given by UNSCEAR in the mining sites and even at 500 m away from the mining site. At 1 Km away from the mining site the activity measured is within the limit for normal background. The ratio of activity of Thorium to Radium is greater by factor of 5 in all the samples in the mining site and 500 m away which should be about unity. The mean absorbed doses (1828.66, 252.08 and 171.07 nGyh-1) for Site1, Site2 and 500m from mining site respectively in air are equally high compared with (51 nGyh-1). Also, the estimated effective dose equivalents are much higher than the recommended limit except for 1 Km Source: Field Work 2019 from the mining site. Lastly Wapwera, Ayanbimpe and Odita [7], researched on abandoned mines in Jos Plateau Tin-Mining Region, they recorded traces of X-ray, beta-ray and gamma-ray as well as theIJSER heavy metals such as Pb, As, Cu, Cr and Ni which exceeded the international standards. This is particularly significant as people use the contaminated soils as building materials for their homes as well as for farming and food production. The inhabitants of the area are often without any knowledge about the perils of the contaminated soils, water as well as air which is serious long-term human catastrophe. Drawing from international experience, the paper argues that it is possible to develop housing in former tin-mining areas but requires careful remediation and engagement by the public and private sector.

5 Result and Discussion The results of assessment of radiation measured at selected tin mining sites in Jos south local government area is presented figure 3 and 5, Geographic information system was used to depict radiation and temperature data obtained from the month of March and July, the used of interpolation model to depict these data gives a clearer view on the variation of data obtained from this two month Figure 4: Map of March Temperature Measured. which are presented Source: Field Work 2019

Figure 3 shows that the mean value of radiation readings collected in March is 0.3227 μSvh-1. The highest reading of radiation was 0.72 μSvh-1 which is located at Rayfield, while the lowest was 0.17 μSvh-1 which may be regarded as NORM. These values indicate that at 0.72 μSvh-1 if calculated for a year would be about 6307.2 μSvy-1 which is above 3.0 mSv/year global average annual dose per person from all sources of radiation in the environment [19]. The highest point was located at Rayfield North of Jos South; this might be due to the high presence of Uranium, thorium and/or potassium which are radionuclide in nature as observed by Odusote et al [20]. The March temperature readings as express in figure 4, indicates that the highest and lowest reading on the days when samples were collected was 360C and 320C respectively and as observed by Eziashi [21] two distinct season (wet and dry) has a temperature range of 320C to 180C respectively, this directly conforms to the measurements as shown in figure 4. The mean temperature is 33.910C with a standard deviation of 1.375 which indicate that temperature were stable during the periods samples were collected, this may not have huge impact on the radiation readings obtained as at the time temperature readings were taken. From figure 3 and 4, it Figure 6: Map of July Temperature Measured. could be noticed that the region with highest radiation level Source: Field Work 2019. also recorded a high temperature reading of 340C which was taken around 1:58pm. Figure 5 shows radiation readings collected at various sampling point within Jos South Local Government Area of Plateau State in month of July. The highest recorded radiation reading was 0.67 μSvh-1 (5956.8 μSvy-1) this is also above the annual dosage limit a human is IJSER expected to be exposed to according UNSCEAR[19] which is set at 1mSv, while the lowest recorded was 0.13 μSvh-1

(1401.6 μSvy-1). These level of radiation may not really pose an immediate threat to the inhabitants of the regions where high radiation readings are taken according to Ministry of Public Works and Government Services Canada (PWGSC) [22].While the temperature reading for the month of July during the days when samples were collected were relatively colder than that of March as expected, the lowest

temperature readings is below 240C while the highest was 0 0 above 31 C, with mean of 29.18 C as shown in figure 6, with a standard deviation of 2.750. This reading conforms to the seasonal temperature of Nigeria. The radiation readings were a bit lower than those recorded in March, this may be attributed to the high rainfall which according to Dung- Gwom et al [23] peaks at the month of July and August, therefore readings are expected to be lower due to cloud cover. The mean annual rainfall is between 1347.5mm per Figure 5: Interpolation Map of July Radiation Measured. annum; this high rainfall washes off the surface of the piled Source: Field Work 2019. byproduct of tins and reduces the amount of concentrated minerals emitting radiation through leaching. Surface

IJSER © 2021 http://www.ijser.org International Journal of Scientific & Engineering Research Volume 12, Issue 7, July-2021 352 ISSN 2229-5518 runoff which concentrate these minerals when settled, are later absorbed by plants and consumed by herbivores and passed from animal up the food chain, thereby increasing the radiation intake up the food chain. Muhammed et al [24], observed that high value of uranium obtained in cereals and vegetables can be attributed to the fact that some of the cereals (corn) and vegetables are phytoremediators in a uranium contaminated soil because of their high bioaccumulation of uranium.

6 Seasonal Variation in the Amount of Emitted Radiation It was estimated that the inhabitants of these Analysis of seasonal variation in the amount of regions are exposed to an average annual radiation dose of emitted radiation, using readings from month of March and 3.7 mSvy-1 and up to 6.3 mSvy-1 in dry season and 5.9 mSvy- July is presented in figure 7. Among the eleven (11) sample 1 in rainy season, with a mean of 2843.02 μSvy-1 for the points measured, only one (1) sample point was month of March and 2476.62 μSvy-1 for July as shown in radioactively alarming as shown in figure 7 and projected figure 8. These values are higher than the study by Sadiq et in figure 8, which is located at Rayfield, just behind the Golf al [25] who reported values of 1.04 to 1.75mSv/yr and 0.24 club, which lies on latitude 9° 49' 50"N and longitude 8° 54' to 0.44mSv/yr for indoor and outdoor radiation at 49"E. This point has the highest average reading both in Akwanga, Nigeria respectively. March and July of over 0.65 μSvh-1. 7 Statistical Analysis of Seasonal Variation of Radiation.

Table 1. Statistical Analysis of March and July radiation

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In a study conducted by Ekong et al (2019), radiation measurements obtained were from 0.041 ± 0.002 - 0.045 ± 0.002 µSv/hr with overall mean of 0.042 ± 002 µSv/hr which indicate an increase in the exposures to background ionizing radiation which can lead to Excess Life Cancer Source: field work 2019 Risk at 0.05 × 10-3. An increase in the background ionizing radiation means a possibility of an increase in the cancer The result of the Wilcoxon test is depicted in table 1, the z- patient within the same environment, based on the Excess values is -2.814 and since the alpha level is set at 95% that is Life Cancer Risk at 0.05 × 10-, the radiation readings in 0.05 and the p-value of 0.005 is less than the alpha level, figure 7 shows that readings far exceed those observed by therefore it can be concluded that there is a significant Ekong et al [26] and the world radiation measurement variation in the amount of emitted radiation between mean of 0.2 µSv/hr, which indicate a possibility in the March and July readings obtained. In a similar study, increase of cancer patients with the environs over time. Akpootu et al [27] observed that radiation peaks were observed around February, March and April while the minimum was recorded around June and October; this explains maximum incident solar radiation during the dry 8 Annual Projected Radiation Readings at season than wet season. Sample Sites against ICRP Standard.

Table 2: Correlations between Radiation and Temperature Readings for both March and July 10 REFERENCE [1] Canadian Nuclear safety Commission (2014) the CNSC’s Radon and Health document (INFO-0813) at nuclearsafety.gc.ca or visit Health Canada's Web site (hc-sc.gc.ca) to learn more about the means to control it in your home. [2] United Nations Scientific Committee on the Effects of Atomic Radiation, 61st session (21-25 July 2014)

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